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United States Patent |
5,335,125
|
Nakatsu
,   et al.
|
August 2, 1994
|
Video signal magnetic recording and reproducing apparatus
Abstract
A video tape recorder capable of recording a normal definition video signal
and a high definition video signal having an image quality higher than the
normal one in a simulcast for broadcasting an identical program in a
conventional broadcasting system and a high definition system. The common
video signal is recorded in a conventional analog signal format at a tape
feeding speed of the normal mode by an EP mode head defining a tracking
width narrower than that of a standard mode head, while the high
definition video signal is recorded in a digital form by a high definition
video head additionally mounted on a rotary drum. Additionally, a common
video signal recorded by a conventional video tape recorder can be
reproduced.
Inventors:
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Nakatsu; Etsuto (Osaka, JP);
Morioka; Yoshihiro (Osaka, JP);
Kobayashi; Masaaki (Kawanishi, JP)
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Assignee:
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Matsushita Electric Industrial Co., Ltd. (Osaka, JP)
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Appl. No.:
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969482 |
Filed:
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October 30, 1992 |
Foreign Application Priority Data
Current U.S. Class: |
386/67; 386/92; 386/112; 386/123; 386/124 |
Intern'l Class: |
H04N 005/78 |
Field of Search: |
360/32,33.1,21,64,10.1,10.3
358/341,141,312,310,335,12,15
|
References Cited
U.S. Patent Documents
4656527 | Apr., 1987 | Uchimi | 358/320.
|
4862292 | Aug., 1989 | Enari et al. | 360/33.
|
4963991 | Oct., 1990 | Honjo | 360/9.
|
5050010 | Sep., 1991 | Park | 360/33.
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5065259 | Nov., 1991 | Kubota et al. | 360/32.
|
Foreign Patent Documents |
59-104703 | Jun., 1984 | JP.
| |
59-221802 | Dec., 1984 | JP.
| |
2-239785 | Sep., 1990 | JP.
| |
Other References
English Abstract of Document No. 2-239785, Yokodera VTR Device, Sep. 21
1990.
English Abstract of Document No. 59-221802, Takeuchi, Magnetic Recording
and Reproducing Device, Dec. 13, 1984.
English Abstract of Document No. 59-104703 Minoura, Signal Recording method
on Video Tape, Jun. 16, 1984.
|
Primary Examiner: Sniezek; Andrew L.
Attorney, Agent or Firm: Ratner & Prestia
Claims
What is claimed is:
1. A video signal magnetic recording and reproducing apparatus capable of
recording and reproducing a video signal in a standard speed mode and an
extended play (EP) mode and capable of simultaneously recording and
reproducing a composite video signal consisting of a first video signal
with normal definition and a second video signal with high definition in a
simulcast for broadcasting an identical program in both a conventional
broadcasting system and a high definition broadcasting system, said video
signal magnetic recording and reproducing apparatus comprising:
a rotating drum including
a first magnetic head pair for recording and reproducing the video signal
in the standard speed mode,
a second magnetic head pair for recording and reproducing the video signal
in the EP mode and for recording and reproducing the first video signal in
the standard speed mode and
a third magnetic head pair for recording and reproducing the second video
signal in the standard speed mode, said third magnetic head pair having an
azimuth angle different from those of the first and second magnetic head
pairs;
a magnetic recording medium in which said first and second video signal are
recorded;
first recording signal processing means for receiving and processing the
first video signal to obtain an analog recording signal which is to be
recorded onto a first track pattern formed on said magnetic recording
medium by the second magnetic head pair at the standard speed mode;
second recording signal processing means for receiving and processing the
second video signal to obtain an analog recording signal which is to be
recorded onto a second track pattern formed on said magnetic recording
medium by the third magnetic head pair at the standard speed mode, wherein
the analog recording signal and the digital recording signal are
simultaneously recorded in a simulcast such that each track of said second
track pattern is adjacent to each track of said first track pattern;
first reproduction signal processing means for processing a recorded first
video signal reproduced from said magnetic recorded medium by any one of
said first and second magnetic head pairs to output a reproduction first
video signal; and
second reproduction signal processing means for processing a recorded
second video signal reproduced from said magnetic recorded medium by said
third magnetic head pair to output a reproduction second video signal when
reproducing the recorded second video signal in a simulcast.
2. The apparatus as claimed in claim 1, wherein said second recording
signal processing means further comprises
an analog-to-digital converter unit for converting said second video signal
from an analog form into a digital signal and
an image data compression unit for compressing the digital signal in data
amount.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording and reproducing apparatus, and
in more particular, to a video signal magnetic recording and reproducing
apparatus such as a video tape recorder (VTR).
2. Description of the Prior Art
A conventional VTR has two tape feeding modes, one is a standard speed mode
and the other is a one-third speed mode having a recording time period
extended three times longer than that of the standard speed mode. In the
one-third speed mode (referred to as "EP mode" hereinafter), there is used
a magnetic head for the EP mode forming a track pattern having a track
width reduced one-third of that of a standard speed mode head, enabling to
record and reproduce a video signal at the tape feeding speed reduced to
one third of the speed in the standard mode.
FIG. 7 shows a head arrangement of a conventional VTR in which a pair of
standard mode heads 1 and 2 and another pair of EP mode heads 3 and 4 are
mounted on a rotating drum 5, where the head members of each head pair are
arranged in opposite directions at an angle of 180 degrees with respect to
the rotating axis of the drum 5. A video signal is recorded as magnetic
patterns on a magnetic tape 6.
FIG. 8 shows a recording track pattern when in the standard speed mode
where the recording track width is approximately 58 .mu.m.
Also, FIG. 9 shows a recording track pattern when in the EP mode where the
recording track width is approximately 19 .mu.m.
The signal to be recorded on a magnetic tape is a composition signal formed
by multiplexing in frequency a frequency-modulated luminance signal and a
down-converted chrominance signal, and the frequency allocation of the
composition signal is generally indicated as shown in FIG. 3 the
description of which is referred to later.
In a conventional VTR, however, when recording a video signal in a
simulcast for broadcasting an identical program in both a conventional
common broadcasting system and a high definition broadcasting system, the
conventional VTR can only record the video signal in the conventional
common broadcasting system (referred to as "common video signal"
hereinafter), which means that the conventional VTR cannot record the
video signal in the high definition broadcasting system (referred to as
"high definition video signal" hereinafter) having an image quality higher
than that of the common video signal.
SUMMARY OF THE INVENTION
Accordingly, an essential object of the present invention is to provide a
video signal magnetic recording and reproducing apparatus capable of
simultaneously recording and reproducing a conventional common video
signal and a high definition video signal in simulcast while assuring the
capability of reproducing a video signal recorded by means of a
conventional VTR.
In order to achieve the above-mentioned objective, the present invention
provides a video signal magnetic recording and reproducing apparatus which
is capable of recording and reproducing a video signal in a standard mode
as well as in a EP mode and also capable of simultaneously recording and
reproducing a common video signal and a high definition video signal in
simulcast for broadcasting an identical program in both a common
broadcasting system and a high definition broadcasting system.
The video signal magnetic recording and reproducing apparatus of the
present invention is characterized in that, on a rotating drum there are
further provided a pair of high definition video heads having an azimuth
angle different from the azimuth angle of each of a standard mode head
pair and of a EP mode head pair provided besides. When simultaneously
recording a common video signal and a high definition video signal, the
common video signal is processed into an appropriate analog form through a
first recording signal processing circuit and then recorded as a magnetic
track pattern onto a magnetic tape by means of the EP mode head pair at a
tape feeding speed of the standard mode, while the high definition video
signal is processed into an appropriate digital form through a second
recording signal processing circuit and then recorded by means of the high
definition video head onto a track adjacent to each of the tracks on which
the common video signal is recorded. When simultaneously reproducing the
common video signal and high definition video signal recorded on the
magnetic tape, the recorded common video signal is reproduced through the
standard mode head or the EP mode head and then processed through a first
reproduction signal processing circuit so as to be reproduced, while the
recorded high definition video signal is reproduced through the high
definition video head and then processed through a second reproduction
signal processing circuit so as to be reproduced.
With the arrangement mentioned above, since the common video signal is
recorded at the tape feeding speed of the standard mode by means of the EP
mode head having a track width narrower than that of the standard mode
head, therefore a high definition video signal can be simultaneously
recorded by means of the other head. The common video recording signal
format of the present apparatus is substantially the same as that of any
conventional VTR except that the recording track width is narrower, and
therefore any conventional image recorded by means of any conventional VTR
can be reproduced by means of the apparatus of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and features of the present invention will become
apparent from the following description taken in conjunction with the
preferred embodiment thereof with reference to the accompanying drawings,
in which:
FIG. 1 is a schematic view of a head arrangement of a rotary drum of a
video signal magnetic recording and reproducing apparatus in accordance
with a first embodiment of the present invention;
FIG. 2 is a block diagram of a video signal magnetic recording and
reproducing apparatus of the first embodiment according to the present
invention;
FIG. 3 is a graph showing a recording signal frequency allocation at the
time of recording a common video signal;
FIG. 4 is a schematic view of recording tracks of a common video signal and
a high definition video signal recorded simultaneously;
FIGS. 5 is a schematic view of a head arrangement of recording head pairs
where an audio head pair concurrently serves as a high definition
recording head;
FIG. 6 is a block diagram of a video signal magnetic recording and
reproducing apparatus in accordance with a second embodiment of the
present invention;
FIG. 7 is a schematic view of a head arrangement on a rotary drum of a
conventional VTR;
FIG. 8 is a schematic view of recording tracks on a tape where a video
signal is recorded in a standard mode by means of a conventional VTR; and
FIG. 9 is a schematic view of recording tracks on a tape where a video
signal is recorded in an EP mode by means of a conventional VTR.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Before the description proceeds, it is noted that since the basic structure
of the video signal recording and reproducing apparatus of the present
invention is similar to that of the conventional one, like parts are
designated by the same reference numerals throughout the drawings.
FIG. 1 shows a magnetic head arrangement provided on a rotary drum of a
video signal magnetic recording and reproducing apparatus in accordance
with a first embodiment of the present invention.
Referring to FIG. 1, there are mounted a pair of standard mode magnetic
recording heads 1 and 2 for use in a standard speed mode and a pair of EP
mode magnetic recording heads 3 and 4 for use in an EP mode on a rotary
drum 5 in a similar manner to a conventional one, where the members of
each of the recording head pairs are arranged in opposite directions at an
angle of 180 degrees. In addition to the head pairs, another pair of high
definition video magnetic recording heads 7 and 8 are mounted in opposite
directions at an angle of 180 degrees.
The high definition video heads 7 and 8 have azimuth angles different from
the azimuth angles of the standard mode head pair and the EP mode head
pair. For instance, the azimuth angle of each of the standard mode heads
(1, 2) and the EP mode heads (3, 4) is .+-.6 degrees, while the azimuth
angle of the high definition video heads (7, 8) is .+-.30 degrees. It is
noted that the azimuth angle of the high definition video heads (7, 8) may
be, for example, .+-.15 degrees or .+-.20 degrees other than .+-.30
degrees. Designated by reference numeral 6 is a magnetic tape serving as a
magnetic recording medium.
The following describes the operation of the present embodiment having a
rotary drum constructed as mentioned above with reference to FIG. 2.
In a simulcast for simulcasting an identical program in both a conventional
broadcasting system and a high definition broadcasting system, when a
common video signal of an analog form and a high definition video signal
of an analog form are simultaneously recorded onto the magnetic tape 6, a
simulcast recording mode is selected by means of a mode selection switch
(not shown) which selects one mode between the normal broadcast recording
mode and the simulcast recording mode. When the simulcast recording mode
is selected, the EP mode head pair 3 and 4 are selected as a magnetic
recording head pair for recording a common video signal, while the high
definition video head pair 7 and 8 are selected as a magnetic recording
head pair for recording a high definition video signal. At the same time,
the standard tape feeding speed is selected as a tape feeding speed.
The common video signal of an analog form is input to an input terminal 9,
while the high definition video signal is input to another input terminal
16. The common video signal 91 input through the input terminal 9 is
separated into a luminance signal 101 and a chrominance signal 102 by
means of a Y/C separation circuit 10. The luminance signal 101 is
transmitted via an emphasis circuit 11 to a frequency modulation circuit
12 to be modulated in frequency. Meanwhile, the chrominance signal 102 is
subject to a down-conversion in a down-conversion circuit 13. The
frequency-modulated luminance signal 121 output from the FM circuit 12 and
the down-converted chrominance signal 131 output from the down-conversion
circuit 13 are added together in an adder 14 and then transmitted to a
recording amplifier 15. The resultant amplified analog signal 151 is fed
to the EP mode heads 3 and 4 provided on the rotary drum 5 so as to be
recorded on the magnetic recording tape 6.
FIG. 3 shows a frequency allocation of the recording analog signal 151
output from the recording amplifier 15, where the frequency-modulated
luminance signal 121 has a relatively high frequency while the chrominance
signal 131 has a relatively low frequency. The luminance FM signal 121 has
a former synchronization edge at a frequency of approximately 3.4 MHz and
a latter peak edge representing 100% white luminance at a frequency of
approximately 4.4 MHz. Therefore, the frequency deviation width becomes
1.0 MHz. Meanwhile, the down-converted chrominance signal 131 has a peak
value at its center frequency of approximately 629 kHz.
Referring back to FIG. 2, the magnetic tape 6 is fed at a tape feeding
speed of the standard mode. The recording analog signal 151 is recorded
onto the magnetic tape 6 by means of the EP mode heads 3 and 4 to thereby
complete the record of the common video signal.
Meanwhile, regarding to the high definition video signal 161 of an analog
form input through the input terminal 16, a sync signal 171 is separated
from the high definition video signal 161 by means of a sync separation
circuit 17 to generate a clock signal 181 having a cycle of 1/N (N:
integer) of the sync pulse interval through a phase-locked loop (PLL)
circuit 18. The high definition video signal 161 is converted into a
digital signal 191 at the timing of the clock signal 181 in an
analog-to-digital converter 19. When an 8-bit analog-to-digital converter
is used, the data amount of the digital signal 191 is 8.times.N bits per a
sync signal interval. The digital signal 191 is compressed in data amount
by an image data compression circuit 20. As a data compression method, a
well-known method of DCT (Discrete Cosine Transform) or the like is used.
The digital signal compressed in data amount incorporates therein error
correction data by means of an error correction data incorporation circuit
21. As an error correction method, well-known reed-solomon error
correction codes or the like method are used. The digital signal
incorporated with the error correction data is modulated by means of a
modulation circuit 22. As a modulation method, a well-known scrambled NRZ
modulation method or eight-to-ten conversion method is used. The modulated
signal is transmitted via a recording amplifier 23 to the high definition
video heads 7 and 8 on the rotary drum 5 thereby to record a high
definition image on the magnetic tape 6.
As shown in FIG. 4, the magnetic recording tape 6 having both the common
video signal and the high definition video signal recorded thereon has a
track arrangement where a common video signal recording track 30 and a
high definition video signal track 31 are formed in adjacent alternately
one after another and the width of the two kinds of the tracks 30 and 31
is approximately 58 .mu.m, wherein the width of the high definition video
signal track 31 is approximately two times as that of the common video
signal track 30.
Referring back to FIG. 2, with regard to the reproducing operation of the
recorded video signals, the common video signal recorded on the common
video signal recording track 30 is reproduced by means of the EP mode
heads 3 and 4 or the standard speed mode heads 1 and 2. The reproduced
common video signal of an analog form is input via a head amplifier 24 to
an analog video signal reproduction circuit 25. The analog video signal
reproduction circuit 25 performs signal processing operations counter to
the signal recording processing operations performed by means of the
circuits 10 through 14. In more detail, a reproduced luminance signal is
demodulated in frequency to be formed into a reproduction luminance
signal, while a reproduced chrominance signal is converted into a
reproduction chrominance signal. The reproduction luminance signal and the
reproduction chrominance signal are added to be output from an output
terminal 26 as a reproduction common video signal 251.
Meanwhile, the high definition video signal recorded on the high definition
video signal recording track 31 is reproduced by means of the high
definition video heads 7 and 8. The reproduced high definition video
signal of a digital form is input via a head amplifier 27 to a digital
video signal reproduction circuit 28. The digital video signal
reproduction circuit 28 performs a signal processing operations counter to
the signal recording processing operations performed by means of the
circuits 17 through 22. In more detail, the circuit 28 detects a digital
signal, corrects errors, expands the compressed digital signal into the
original signal, and converts the signal from digital form to analog form
thereby to output the resulting signal from an output terminal 29 as a
reproduction high definition video signal 281.
Although the above described the case where a common video signal and a
high definition video signal are recorded or reproduced simultaneously, it
is noted here that, when a common video signal is only recorded and
reproduced, the normal broadcast recording mode is selected by means of
the mode selection switch, any one of the tape feeding speed modes is
selected between the standard mode and the EP mode. Thus, the recording
and reproducing operation of only the common video signal is performed by
means of the head pair corresponding to the selected tape speed mode at a
corresponding tape feeding speed.
A second embodiment of a video signal magnetic recording and reproducing
apparatus according to the present invention is explained with reference
to FIGS. 5 and 6.
As shown in FIG. 5, on the rotary drum 5 there are provided a pair of audio
heads 32 and 33 in opposite directions at an angle of 180 degrees instead
of providing a pair of high definition video heads. The audio heads serve
as magnetic recording heads for recording an audio signal in a digital
form and have an azimuth angle of .+-.30 degrees. The audio heads 32 and
33 may concurrently serve as high definition video heads. With the above
arrangement, the high definition video heads can be eliminated with the
provision of a selecting function between a high definition video signal
and an audio signal, thereby enabling to reduce the manufacturing cost.
The following describes the operation of the second embodiment with
reference to FIG. 6. Since the operation of the second embodiment shown in
FIG. 6 is basically similar to that of the first embodiment shown in FIG.
2, redundant explanation is omitted here. In a recording and reproducing
operation in simulcast, a different point between the first embodiment and
the second embodiment is only in that the audio heads 32 and 33 are used
instead of the high definition video heads 7 and 8.
In a case where only a common video signal is recorded and reproduced, the
recording and reproducing operation is performed by means of a
corresponding head pair at a tape feeding speed corresponding to any one
mode selected between the standard speed mode and the EP mode. In this
case, the audio heads 32 and 33 are used for recording and reproducing an
audio signal.
As shown in FIG. 6, when in the operation of recording an audio signal 361
of an analog form, the audio signal 361 input to an input terminal 36 is
converted into a digital form by means of an analog-to-digital converter
37. The digital signal incorporates therein error correction data by means
of an error correction data incorporation circuit 38. The digital signal
incorporated with the error correction data is modulated by means of a
modulation circuit 39. The modulated signal is transmitted via a recording
amplifier 40 to the audio heads 32 and 33 on the rotary drum 5 so as to be
recorded on the magnetic tape 6.
When in the operation of reproducing the recorded audio signal, the audio
signal recorded on the magnetic tape 6 is reproduced by means of the audio
heads 32 and 33, and thereafter input to a digital audio signal
reproduction circuit 42 via a head amplifier 41. The digital audio signal
reproduction circuit 42 performs signal processing operations counter to
the signal recording operations performed by means of the circuits 37
through 39. In other words, in the circuit arrangement 42, the digital
audio signal is detected and the error is corrected so as to be converted
into a digital form. The converted digital signal is output from an output
terminal 43 as an audio reproduction signal 422.
Although the present invention has been fully described by way of examples
with reference to the accompanying drawings, it is to be noted here that
various changes and modifications will be apparent to those skilled in the
art. Therefore, unless otherwise such changes and modifications depart
from the scope of the present invention as defined by the appended claims,
they should be construed as included therein.
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